[BUGFIX 8/9] ACPI: introduce several helper functions

[Jiang Liu <jiang.liu@huawei.com>]

Introduce several helper functions, which will be used to simplify code.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
 drivers/acpi/utils.c    | 74 +++++++++++++++++++++++++++++++++++++++++++++++++
 include/acpi/acpi_bus.h |  5 ++++
 2 files changed, 79 insertions(+)

diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 74437130..cb66fce 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -495,3 +495,77 @@ acpi_handle_printk(const char *level, acpi_handle handle, const char *fmt, ...)
 	kfree(buffer.pointer);
 }
 EXPORT_SYMBOL(acpi_handle_printk);
+
+/**
+ * acpi_evaluate_ej0: Evaluate _EJ0 method for hotplug operations
+ * @handle: ACPI device handle
+ *
+ * Evaluate device's _EJ0 method for hotplug operations.
+ */
+acpi_status acpi_evaluate_ej0(acpi_handle handle)
+{
+	acpi_status status;
+	union acpi_object arg;
+	struct acpi_object_list arg_list;
+
+	arg.type = ACPI_TYPE_INTEGER;
+	arg.integer.value = 1;
+	arg_list.count = 1;
+	arg_list.pointer = &arg;
+	status = acpi_evaluate_object(handle, "_EJ0", &arg_list, NULL);
+	if (status == AE_NOT_FOUND) {
+		acpi_handle_warn(handle, "No _EJ0 support for device\n");
+	} else if (ACPI_FAILURE(status)) {
+		acpi_handle_warn(handle, "Eject failed (0x%x)\n", status);
+	}
+
+	return status;
+}
+
+/**
+ * acpi_evaluate_lck: Evaluate _LCK method to lock/unlock device
+ * @handle: ACPI device handle
+ * @lock: lock device if non-zero, otherwise unlock device
+ *
+ * Evaluate device's _LCK method if present to lock/unlock device
+ */
+acpi_status acpi_evaluate_lck(acpi_handle handle, int lock)
+{
+	acpi_status status;
+	union acpi_object arg;
+	struct acpi_object_list arg_list;
+
+	arg_list.count = 1;
+	arg_list.pointer = &arg;
+	arg.type = ACPI_TYPE_INTEGER;
+	arg.integer.value = !!lock;
+	status = acpi_evaluate_object(handle, "_LCK", &arg_list, NULL);
+	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
+		if (lock)
+			acpi_handle_warn(handle,
+				"Locking device failed (0x%x)\n", status);
+		else
+			acpi_handle_warn(handle,
+				"Unlocking device failed (0x%x)\n", status);
+	}
+
+	return status;
+}
+
+/**
+ * acpi_has_method: Check whether @handle has a method named @name
+ * @handle: ACPI device handle
+ * @name: name of object or method
+ *
+ * Check whether @handle has a method named @name.
+ */
+int acpi_has_method(acpi_handle handle, char *name)
+{
+	acpi_status status;
+	acpi_handle tmp;
+
+	status = acpi_get_handle(handle, name, &tmp);
+
+	return ACPI_FAILURE(status) ? 0 : 1;
+}
+EXPORT_SYMBOL(acpi_has_method);
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 636c59f..5df5f89 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -56,6 +56,11 @@ acpi_evaluate_hotplug_ost(acpi_handle handle, u32 source_event,
 
 acpi_status
 acpi_get_physical_device_location(acpi_handle handle, struct acpi_pld_info **pld);
+
+acpi_status acpi_evaluate_ej0(acpi_handle handle);
+acpi_status acpi_evaluate_lck(acpi_handle handle, int lock);
+int acpi_has_method(acpi_handle handle, char *name);
+
 #ifdef CONFIG_ACPI
 
 #include <linux/proc_fs.h>
-- 
1.8.1.2